The present invention relates to the preparation of concentrated extracts by dehydration of aqueous food or pharmaceutical products, notably -- although not exclusively -- concentrated extracts of materials of vegetal origin, such as fruit juices and infusions of seeds, of leaves or of flower tops, for example infusions of tea and especially of coffee.
Processes for the preparation of concentrated extracts of tea and coffee in powder or granular form are already known. However, they are not entirely satisfactory: they are complex and/or subject the product to drastic physical or chemical actions which degrade it and cause a loss of aroma which it is later necessary to compensate by addition of supplementary constituents.
It is an object of the present invention to provide an improved method and device which overcome the above-mentioned drawbacks.